Question

Conversion of ${ N{ O }_{ 3 } }\longrightarrow { N{ O }_{ 2 } }\longrightarrow { N{ H }_{ 3 } }$ is __________and is catalyzed by _________.
(a)Nitrate assimilation, nitrate, and nitrite reductases.
(b)Nitrification, nitrate, and nitrite reductase.
(c)Ammonification, glutamate reductase
(d)Denitrification, Transaminase

Answer 1

Hint: The process where the conversion of nitrates to ammonia occurs is a reductive process and involves coenzymes like NADPH and FAD/FMN. It is a two-step process and the second step requires ferredoxin as a catalyst.

Complete answer:
The Formation of different organic nitrogen compounds from inorganic nitrogen compounds is called Nitrogen assimilation. It occurs in the following steps:
Nitrate is transported into cells and is converted by nitrate reductase present in the cytosol into nitrite.
Nitrite is then transported into chloroplasts (in case of plants), where it is converted by nitrite reductase into ammonia.

Additional Information:
Nitrification is the process in which ammonia gets converted to nitrite and then to nitrate and is another important step in the global nitrogen cycle. Most nitrification occurs aerobically and is administered exclusively by prokaryotes. There are two distinct steps of nitrification that are administered by distinct sorts of microorganisms. The first step is that the oxidation of ammonia to nitrite, which is administered by microbes referred to as ammonia-oxidizers. Aerobic ammonia oxidizers convert ammonia to nitrite via the intermediate hydroxylamine, a process that requires two different enzymes, ammonia monooxygenase and hydroxylamine oxidoreductase. The process generates a very small amount of energy relative to several other sorts of metabolism; as a result, nitrosofiers are notoriously very slow growers. Additionally, aerobic ammonia oxidizers also are autotrophs, fixing $C{ O }_{ 2 }$ to supply organic carbon, very similar to photosynthetic organisms, but using ammonia because of the energy source rather than light.

So, the correct answer is, ‘’Nitrate assimilation, nitrate and nitrite reductases.’’

Note: The organic process where ammonium (${ NH }_{ 4 }^{ + }$) is oxidized and converted into the nitrate (${ NO }_{ 3 }^{ - }$) is named nitrification, while denitrification is a process involving the conversion of nitrate (${ NO }_{ 3 }^{ - }$) into nitrogen gas. It is carried out by bacterias like Pseudomonas denitrificans, Thiobacillus denitrificans.